Description from Flora of China
Lemma Adanson; Spheroidia Dulac; Zaluzianskia Necker.
Fronds in deeper water with stipes lax and slender and pinnae floating upon water surface; fronds in shallow water or on land with erect stipes and pinnae oriented in various positions by action of basal pulvini; pinnae 4, obtriangular to fan-shaped, clustered at tip of stipe. Veins of pinnae forking dichotomously, anastomosing to form elongate areoles. Sporocarps 1 to many per frond, quadrate to elliptic in lateral view, leathery to woody when mature. Sori oblong, with few megasporangia and numerous microsporangia in each sorus. Megaspore ovoid-globose with a terminal papilla; spore wall thin, indistinctly reticulate. Microspores globose; spore wall thin, indistinctly sculptured. x = 20.
Dimensions of vegetative parts of all species can vary greatly in size depending upon water levels and season of the year; frond dimensions in the descriptions are from emergent or land fronds, not floating ones.
About 52 species: worldwide, with centers of diversity in tropical Africa and Australia; three species in China.